Firestorm

20

Fire 100 nukes.

This is easily done when going for the Economy of Grand Scale: Mass achievement. While you are idling and letting your mass accumulate simply build 5 or so nuke silos and when they are complete shoot them into a unoccupied area, my suggestion is way out at sea. Click out into the water about 100 times so that all the nukes will fire on their own instead of you having to manually target each one now they will fire immediately after a new nuke is built. After all 5 are built you should unlock this achievement before you've unlocked the Economy of Grand Scale: Mass achievement.